JPH07183279A - Processing unit - Google Patents

Abstract

PURPOSE:To provide a processing unit able to maintain a horizontal degree to the holding surface of a body to be processed on a mounting stand holding a body to be processed while allowing uniform processing of a body to be processed even in case of generated thermal expansion or thermal shrinkage accompanying a processing temperature processing the body to be processed. CONSTITUTION:This is a processing unit holding a body W to be processed on a mounting stand 6 while heating the body W to be processed or/and generating plasma so as to process by means of active species in the plasma and at least the holding surface holding the body W to be processed of the mounting stand 6 is provided with a polybenzazole film 9.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a processing apparatus.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication No. 1-298721 discloses an electrostatic chuck mechanism for electrostatically adsorbing a sample fixed on a sample table provided in a vacuum container. The electrostatic chuck mechanism of this technology is configured by covering the upper and lower surfaces of electrodes connected to a DC power source through a high frequency cutoff circuit with a flexible sheet material made of a polyimide resin film as first and second insulating layers. The sample was placed on the polyimide resin film, and the DC power was turned on to adsorb and hold the sample by electrostatic force.

[0003]

However, when a polyimide resin film is used on the surface of the electrostatic chuck mechanism that holds and holds the sample, generally, an organic adhesive such as an organic adhesive, for example, is used as an adhesive for bonding the sample stand and the polyimide resin film. Since an epoxy adhesive is used and the heat resistant temperature of this adhesive is about 150 ° C., the processing temperature for processing the sample could not be higher than that temperature. Further, in the case of a semiconductor processing apparatus, the sample stage is usually formed of a member obtained by subjecting an aluminum base material to an alumite treatment, and the coefficient of thermal expansion of this aluminum is approximately 2.3 × 10 ⁻⁵ / ° C. Yes,
The coefficient of thermal expansion of the polyimide resin film is about 5 × 10 ^-5 / ° C.
Therefore, when the electrostatic chuck mechanism is heated or cooled due to the difference in the coefficient of thermal expansion, there is a problem that the polyimide resin film is peeled off from the sample table. Further, when the sample is adsorbed and held on the polyimide resin film of the electrostatic chuck mechanism and plasma is generated, and the sample is processed by this plasma, for example, etching or CVD, the polyimide resin film is treated by ions in the plasma. There was a problem that when impacted, heavy metals such as Mg and Ni contained in the polyimide resin film were released and adhered to the sample, which reduced the yield of the sample. Further, when cleaning the inside of the vacuum container for processing the sample, in plasmaless cleaning, if a corrosive gas such as chlorine-based CLF ₃ gas is used, the polyimide resin film itself is corroded. there were. The present invention focuses on the above problems,
It was created to solve this effectively. An object of the present invention is to maintain the levelness of a mounting table for holding a target object with respect to a target object holding surface even if thermal expansion or contraction occurs due to a processing temperature for processing the target object. It is an object of the present invention to provide a processing device capable of uniformly processing.

[0004]

According to a first aspect of the present invention, an object to be processed is held on a mounting table, and the object to be processed is heated or /
And a treatment apparatus for generating plasma and treating with activated species in the plasma, wherein the holding surface of the mounting table for holding the object to be treated is provided with a polybenzazole film. According to a second aspect of the present invention, an object to be processed is adsorbed and held by a Coulomb force by an electrostatic chuck provided on a mounting table in the processing chamber, and the object to be processed is heated or / and plasma is generated. A treatment device for treating with an active species, wherein at least a holding surface of the electrostatic chuck for adsorbing and holding an object to be treated and / or a joint surface with the mounting table is provided with a polybenzazole film. Is. The invention of claim 3 is characterized in that the temperature for treating the object is a predetermined temperature of -200 ° C to 435 ° C. According to a fourth aspect of the present invention, the electrostatic chuck is configured by sandwiching an electrode plate to which a predetermined voltage is applied between members formed of polybenzazole, or at least two electrodes to which different voltages are applied. It is characterized in that the plate is sandwiched. The invention of claim 5 is characterized in that a polybenzimidazole solution is used as an adhesive for joining the electrostatic chuck and the mounting table. The invention of claim 6 is characterized in that the mounting table is made of aluminum.

[0005]

According to the present invention, at least the holding surface for holding the object to be processed of the mounting table or the holding surface for adsorbing and holding the object to be processed of the electrostatic chuck for adsorbing and holding the object to be processed by Coulomb force and / or the mounting table. Since a polybenzazole film having a coefficient of thermal expansion substantially the same as that of the mounting table is provided on the joint surface of and, the object to be processed can be electrically insulated from the mounting table, and the processing of the object to be processed can be performed. Even if thermal expansion or thermal contraction occurs due to temperature, it is possible to prevent the polybenzazole from peeling from the mounting table.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A plasma etching apparatus as an embodiment of the processing apparatus according to the present invention will be described in detail below with reference to the accompanying drawings.

As shown in FIG. 1, this etching apparatus has a processing container 1 as a processing chamber, which is formed in a cylindrical or rectangular shape from a conductive material, for example, aluminum whose surface is anodized, and the like. A support base 2 for mounting and holding an object to be processed, for example, a semiconductor wafer W is installed in the container 1. The support base 2 is also called a susceptor or the like, and has a multiple structure for combining a cooling jacket for controlling the temperature of the wafer W and a heater. That is, a cylindrical base 4 fixed to the bottom of the processing container 1 via an insulating member, for example, an insulating plate 3 made of ceramics, and a disk-shaped heater placed on the upper surface of the base 4. It has a multiple structure consisting of a fixing base 5 and a mounting base 6 which also serves as a lower electrode and is mounted on the substrate 4 so as to include the heater fixing base 5 from above. The base 4, the heater fixing base 5, and the mounting base 6 are electrically conductive members,
For example formed from aluminum. Each is fastened by bolts so that it can be detached.

Further, the mounting table 6 is in the form of a disk having a convex upper surface center portion, and on the central upper surface, for example, an electrostatic chuck 8 is substantially a wafer W as a chuck portion for holding the wafer W. They are provided with the same diameter, and preferably a diameter slightly smaller than the diameter of the wafer W. As shown in FIG. 2, the electrostatic chuck 8 is a polymeric material and an insulating member, for example, a polybenzazole-based material as shown in a of chemical formula 1, as a surface for mounting and holding the wafer W. Examples of the benzazole-based material include polybenzazoles having different X groups, such as the polybenzimidazole-based material shown in b of Chemical Formula 1 or the polybenzothiazole-based material or Chemical Formula 1 in c of Chemical Formula 1.
The electrostatic chuck sheet 61 is formed by sandwiching a conductive film 60 such as a copper foil between two films 9 formed of a polybenzoxadol-based material shown in d. The coefficient of thermal expansion of the polybenzazole-based material is about 2.3 × 10 ⁻⁵ / ° C., which is substantially the same as the coefficient of linear expansion of the mounting table 6 and the like made of aluminum. Further, the hardness is a material of 125 or more on the E scale, the heat deformation temperature is as high as 435 ° C., and the physical properties are stable at −200 ° C. even at an extremely low temperature.

The mounting table 6 is provided with a through hole 62, and an insulating member, for example, an annular member 63 made of the above-mentioned polybenzazole-based material is disposed in the through hole 62. Inside the annular member 63, a conductive member, for example, a cylindrical conductive pin 64 made of a material such as aluminum is arranged. A connecting conductor 65 of a conductive member is provided above the conductive pin 64, and the conductive pin 64 and the conductive film 6 are interposed via the connecting conductor 65.
0 is electrically connected. Further, the conductive pin 64 is connected to a variable DC high voltage source 67 via a voltage supply lead 66, as shown in FIG. Therefore, by applying a high voltage to the conductive film 60, the wafer W can be attracted and held by the Coulomb force on the electrostatic chuck 8, that is, the upper surface of the film 9.

Further, between the film 9 and the conductive film 60, between the connection conductor 65 and the conductive film 60, between the film 9 and the mounting table 6, between the mounting table 6 and the insulating member, and the conductive pin 6
As a joining method between the 4 and the insulating member 63, first, a polybenzimidazole solution is applied as an adhesive to each joining portion. As the solvent for preparing the polybenzimidazole solution, for example, a polar solvent which is generally used in the production of a dry spinning solution of polybenzimidazole can be used. Preferably, the solvent is at least one solvent selected from the group consisting of N, N-dimethylacetamide, N, N-dimethylformamide, dimethylsulfoxide and N-methyl-2-pyrrolidone, and a particularly preferred solvent is Boiling point is 16
This is N, N-dimethylacetamide at 7 ° C. Further, by adding terpenes such as kerosene or ketones such as methyl ethyl ketone to the solvent as a mixed solvent, the drying efficiency of polybenzimidazole can be improved without impairing the solubility of the solvent. You can

Then, those members are put in a temperature rising furnace,
The temperature is gradually raised from room temperature to a predetermined temperature, for example, about 150 ° C to 220 ° C. The final temperature depends on the boiling point of the solvent in which polybenzimidazole is dissolved. For example, when a solution obtained by dissolving polybenzimidazole in N, N-dimethylacetamide (DMAC) is used, 16
By heating to 7 ° C. or higher, preferably about 180 ° C., N, N-dimethylacetamide is volatilized, and polybenzimidazole is crosslinked and cured to bond the respective members.

Further, as shown in FIG. 1, the wafer W on the electrostatic chuck 8 is surrounded by the central convex portion of the upper surface of the mounting table 6.
An annular focus ring 15 is arranged so as to surround the outer peripheral side. The focus ring 15 is made of an insulating material that does not attract reactive ions, and has a function of effectively causing reactive ions to enter the semiconductor wafer W inside. Cooling means, for example, a cooling jacket (refrigerant annular flow path) 20 is provided in the base 4 for temperature control during the plasma processing of the wafer W placed and held on the support base 2. A coolant such as liquid nitrogen is introduced into the casing 20 through a coolant introduction pipe 21 and circulates in the jacket 20, and a gas produced by evaporation of the liquid nitrogen is discharged from the coolant discharge pipe 22 to the outside of the container. . Also, the cooling jacket 20
A series of gas passages 23 are formed in the base 4 containing therein the heater fixing base 5 and the mounting base 6 on the base 4 in order to improve the electrothermal property to the wafer W. A gas is supplied and heat is transferred to the electrostatic chuck 8.

Further, the heater fixing base 5 interposed between the base 4 and the mounting base 6 has a band having a thickness of about several mm so that the upper surface is flush with the annular recess of the upper surface. A plate-shaped temperature adjusting heater 25 is provided. this is,
A linear or strip-shaped resistance heating element 25a made of, for example, tungsten, carbon, or Fe-Cr-Al alloy is provided inside an insulator made of a sintered body of AlN (aluminum nitride) having excellent thermal conductivity and heat resistance. This resistance heating element 25a receives desired power from the power source 28 via the filter 27 through the power supply lead 26 to generate heat, and the cold heat from the cooling jacket 20 is transferred to the wafer W. The temperature of the wafer W is controlled by appropriately controlling the amount of heat. In addition, a branch passage 23a from the gas passage 23 is formed in the heater fixing base 5 in order to improve heat transfer. In the figure, 30 is the mounting table 6.
A temperature detector for detecting the temperature of the device, the control signal 33 detected by the detector is controlled by the temperature detection lead 31 to monitor the entire device through the high frequency noise removal filter 32, for example, a control unit 33 including a CPU or the like. The temperature of the wafer W is adjusted by automatically controlling the heat generation of the temperature adjusting heater 25 on the basis of this.

Further, in the mounting table 6, a noise cutting filter 38 and a matching member are provided by a hollow pipe lead 36 and a wiring 37 made of a conductor and penetrating a member arranged below the mounting table 6. Through the capacitor 39 for use, for example, 13.56 MHz or 40.68
It is connected to a high frequency power source 40 for generating plasma such as MHz. On the other hand, in the container 1, at a position facing the mounting table 6 and separated by about 15 to 20 mm,
An upper electrode 42 is provided. The upper electrode 42 is
It also serves as a processing gas introduction path, and is in the form of a hollow disk integrally formed of a conductive member such as aluminum, and the electrode portion 42a electrically grounded and a processing gas, for example, an etching gas such as CF4 are contained in the container 1. And a processing gas introduction pipe 42b for supplying the same to the processing gas introduction pipe 42b.
Is connected to the container 1, and is configured to blow out the etching gas into the processing space below through a large number of small holes 42c formed in the surface of the electrode portion 42a.

An exhaust pipe 45 is connected to the lower peripheral side wall of the container 1 as an exhaust path, and the atmosphere in the container 1 is evacuated by an exhaust pump through a valve member (not shown) such as a butterfly valve in the middle of the exhaust path. It is configured so that it can be exhausted. Further, a treatment object loading / unloading port 47 is provided on a side portion of the container 1, and the loading / unloading port 47 can be communicated with or blocked from the load lock chamber 49 via a gate valve 48 which is automatically opened / closed by a drive mechanism (not shown). ing. The gate valve 48 is configured to be in pressure contact with the O-ring 50 so as to airtightly seal the loading / unloading port 47. A transport mechanism 51 such as a handling arm that inserts and removes wafers W to be processed into and out of the container 1 one by one is provided in the load lock chamber 49, and the plasma etching apparatus is configured as described above.

Next, the operation of the present embodiment configured as above will be described. First, open the gate valve 48 with the inside of the load lock chamber 49 isolated from the outside (atmosphere),
The wafer W is loaded from the load lock chamber 49 into the container 1 whose pressure has been reduced to a predetermined pressure, for example, about 1 × 10 −4 to several torr, and the wafer W on the support base 2 is sucked and held on the mounting base 6. It is placed on the electric chuck 8. At this time, a coolant is circulated in the cooling jacket 20 to maintain this portion at −196 ° C., the cold heat from this is transmitted to the wafer W via the mounting table 6, and the heat generation amount of the temperature adjustment heater 25 is controlled. Then, the wafer W is adjusted and maintained at a predetermined temperature, for example, a predetermined temperature in the range of −10 ° C. to −200 ° C. in the case of cold processing. Then, the processing gas is caused to flow into the processing space through the small holes 42c of the upper electrode 42, and the high frequency power supply 40 is turned on, so that the pipe lead 36 is provided between the mounting table 6 as the lower electrode and the upper electrode 42. , Apply high frequency power,
The processing gas is turned into plasma, and the processing surface of the wafer W is etched by the active species in the plasma.

Next, the effect of this embodiment will be described.
Since the surface of the electrostatic chuck 8 on which the wafer W is mounted and held is made of at least a polymer material and a polybenzazole-based material of the insulating member, the occurrence of plasma causes
Even when subjected to the impact of ions in the plasma, the heavy metal such as Mg or Ni is not contained or the content thereof is smaller than that of the conventional polyimide resin film. The amount of adhered substances can be suppressed, and the yield of semiconductor wafers W can be improved.

Further, in the apparatus for processing the semiconductor wafer W by lowering it from room temperature to low temperature or by heating it, the mounting table 6 and the polybenzazole film 9 or the bonding thereof is raised even if the processing temperature is raised to high temperature. Since the agents have substantially the same coefficient of thermal expansion, peeling unlike the conventional polyimide resin film does not occur easily, and the life of the device can be extended. Further, it is possible to solve the problem that the leveling of the mounting surface of the semiconductor wafer W cannot be maintained due to the peeling.

Further, since the surface of the electrostatic chuck 8 on which the wafer W is mounted and held is made of at least a polymer material and a polybenzazole-based material as an insulating member, the holding surface due to contact with the wafer W or the like. In comparison with the conventional polyimide resin film having a hardness of about 99 on the E scale, polybenzazole has a hardness of 125 or more on the E scale, so that it is less likely to be damaged and the life can be extended.

Even if a corrosive gas such as chlorine-based CLF ₃ gas used for cleaning the inside of the container 1 is used, the pressure inside the container 1 is set to 1 Torr and the container 1
700 sccm of CLF ₃ gas and 2800 N ₂ gas
When compared with the data obtained by flowing sccm, the conventional polyimide resin film had an etching rate of 5000 Å / min or more, whereas polybenzazole had an etching rate of 2500 Å / min or less.
ng rate, the progress of corrosion or etching can be suppressed, and the life of the electrostatic chuck itself can be extended.

In the above embodiments, the case where the present invention is applied to a plasma etching apparatus has been described, but the present invention is not limited to this, and a processing apparatus for heating and processing, for example, a range of 30 ° C to 435 ° C. Can be applied to an apparatus for processing an object to be processed at a predetermined temperature, such as a heat treatment apparatus, a CVD apparatus, or a plasma CVD apparatus. In addition, the conductive film was sandwiched by polybenzazole on the electrostatic chuck sheet, but if the temperature is not affected by the thermal expansion coefficient of the mounting table, the film of polybenzazole will be formed on the surface of the conventional polyimide resin film. It may be formed by applying a film of polybenzazole to at least the surface of the chuck formed of ceramic, the chuck formed of Sic, or the chuck formed of other members. Of course. Furthermore, when a mechanical or holding mechanism, such as a mechanical clamp, which presses and holds the peripheral edge of the object to be processed is held on the mounting table, the surface of the mounting table on which the processing object is mounted is used. Alternatively, a film of polybenzazole may be applied. Further, although the example in which the semiconductor wafer is used as the object to be processed has been described, the invention is not limited to this, and a liquid crystal substrate such as an LCD can be used as a matter of course.

[0022]

According to the present invention, the polybenzazole can be prevented from peeling from the mounting table even if thermal expansion or contraction occurs due to the processing temperature for processing the object to be processed. It is possible to maintain the levelness with respect to the object holding surface, uniformly process the object, and improve the yield of the object.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a plasma etching processing apparatus showing an embodiment of a processing apparatus according to the present invention.

FIG. 2 is an enlarged schematic cross-sectional view showing the vicinity of a target object mounting portion of the mounting table of FIG.

[Chemical 1]

[A] is a chemical formula of polybenzazole.

[B] is a chemical formula of polybenzimidazole.

[C] Chemical formula of polybenzothiazole.

[D] is a chemical formula of polybenzoxadol.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Processing chamber 6 Mounting table 8 Electrostatic chuck 9 Film (polybenzazole) 63 Insulating member W Semiconductor wafer (processing target)

Claims (6)

[Claims] 1. A processing apparatus for holding an object to be processed on a mounting table, heating the object to be processed or / and generating a plasma, and processing with active species in the plasma, which is at least the mounting table. A treatment apparatus having a polybenzazole coating on a holding surface for holding the object to be treated. 2. An electrostatic chuck provided on a mounting table in the processing chamber adsorbs and holds the object to be processed by Coulomb force, heats the object to be processed and / or generates plasma, and the activity in the plasma is generated. A processing device for processing by seed,
At least the holding surface of the electrostatic chuck for holding and holding the object to be processed and / or the joint surface with the mounting table is provided with a polybenzazole coating film. 3. The temperature for processing the object is −20.
The processing device according to claim 1, or the processing device according to claim 2, wherein the predetermined temperature is in the range of 0 ° C to 435 ° C. 4. The electrostatic chuck is configured by sandwiching electrode plates to which a predetermined voltage is applied with polybenzazole, or by sandwiching at least two or more electrode plates to which different voltages are applied. The processing device according to claim 2, wherein the processing device is processed. 5. The processing apparatus according to claim 2, wherein a polybenzimidazole solution is used as an adhesive agent for joining the electrostatic chuck and the mounting table. 6. The processing apparatus according to claim 1, or the processing apparatus according to claim 2, wherein the mounting table is made of aluminum.